How exactly are you using causality here. Cause and effect, beginning is a cause. A beginning is the logical construct on which all ration thought on the subject (effects) are based.
But honestly I've had a killer migraine most of the day and can't even see out if my right eye so I'm probably not in a fit state for dabated/conversations on quantum and metaphysical theory. Hopefully tomorrow my brain will have ceased trying to kill me.
This universe probably has a beginning and an end, but as the Big Band theory and the Big Crunch theory are more than valid, it may be possible that the Big Bang of this universe just followed the Big Crunch of the former, and the Big Crunch that will destroy this universe will be immediately followed by the Big Bang of another universe, and so on, meaning that existence may have no beginning and no end, as the universe would just be breathing forever and all that we know of it is fitting in a single loop of an eternal cycle.
Didn't we already establish that?
http://www.hawking.org.uk/the-beginning-of-time.html